<head>

    <link href="https://cdn.bootcss.com/bootstrap/4.0.0-alpha.6/css/bootstrap.css" rel="stylesheet" />
</head>
<body>
    <!-- <scripsst src="https://cdn.bootcss.com/jquery/2.1.4/jquery.min.js"></script> -->
    <h1>我是 h1 标签</h1>

    <!-- <script>
        console.log('888')
    </script> -->
</body>